Fixing contrast during scan

  • Thread starter Thread starter friesian
  • Start date Start date
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friesian

I am having trouble with a series of prints that I am trying to scan.
They are very high contrast with a black background and a white
subject. I don't care about the black, but I am losing detail in the
subject because the scan is increasing the contrast.

I have tried reducing the contrast and/or reducing the brightness, but
any amount that increases detail also seems to dull out the image.

The prints look perfect - sharp and bright, but great detail. The scans
(without adjustment) look too bright, and not so sharp anymore.

I've been trying to play around with curves, and the sliders, and I
just can't come up with the right values to get what I am looking for.
I've been reading the manual, but it doesn't seem to have anything for
this kind of situation.

Any suggestions? I'm scanning these to include in my portfolio, so I
need them to look as good as the prints.

I have a similar series done a few years ago that scanned just fine.
Same subject and lighting, but different scanner and software.

I am currently using the Canoscan 4200F. The window for scanning
options is very different from my older scanner, so I am still learning
how to make the right adjustments in this program.
 
You can make identical scans with different exposure settings and
superimpose them as layers in Photoshop, erasing/painting out as needed,
 
Sounds to me like there is some clipping being done by the software.
Try vuescan, making sure you set it up for no clipping.

Once you are certain no "information" is being lost, set the endpoints
and gamma as best you can, then try bending the curve.
 
[email protected] said:
Sounds to me like there is some clipping being done by the software.
Try vuescan, making sure you set it up for no clipping.

Once you are certain no "information" is being lost, set the endpoints
and gamma as best you can, then try bending the curve.
Click to expand...

Do you have any recommendations for setting these points? I tried some
random numbers to see how it did, and I wasn't happy with my guesses.
 
Generally the scanner software sets the endpoints automatically. With
the clipping set to 0%, statistically the endpoints will be too wide.
Now if you want to pull the endpoints in visually, here is how you do
it in photoshop with "extreme gamma." Now I'm doing this from memory
and I do slide while you do negative, so I might get something
backward, but I'm sure you'll figure it out.

Load the image and go to adjust levels. Set the gamma to 6. The image
gets very white.Slide the left most slider to the right. You will see
black specs appear in the image. Adjust the slider until you see just a
spec or two, or as many specs as you can tolerate. Then set the gamma
to 0.1. This will make the image go black. Slide the right most slider
to the left and white specs will appear. Set the level to as many white
specs as you can tolerate. Now you have set the endpoints, so adjust
the gamma to what you consider acceptable.
 
Generally the scanner software sets the endpoints automatically. With
the clipping set to 0%, statistically the endpoints will be too wide.
Now if you want to pull the endpoints in visually, here is how you do
it in photoshop with "extreme gamma." Now I'm doing this from memory
and I do slide while you do negative, so I might get something
backward, but I'm sure you'll figure it out.

Load the image and go to adjust levels. Set the gamma to 6. The image
gets very white.Slide the left most slider to the right. You will see
black specs appear in the image. Adjust the slider until you see just a
spec or two, or as many specs as you can tolerate. Then set the gamma
to 0.1. This will make the image go black. Slide the right most slider
to the left and white specs will appear. Set the level to as many white
specs as you can tolerate. Now you have set the endpoints, so adjust
the gamma to what you consider acceptable.
Click to expand...


Another way it to do scan two exposure - one for the highlights, the
other for the shadows and combine them in photoshop. CS 2 had HDR 32 bit
image capabilities which make this kind of blending easier and more
predictable.
 
Generally the scanner software sets the endpoints automatically. With
the clipping set to 0%, statistically the endpoints will be too wide.
Click to expand...

It seems like the ideal setting would be outside the endpoints. Rather
than make the lights point brighter, I would rather make it darker,
while not making anything else darker.

I managed to get decent scans by reducing the contrast and reducing the
brightness, but still not as good as my old scanner.

Then i pulled out the negatives for the missing prints, and I found
that the scans from the negatives are much better. My old scanner
wasn't very good with negatives, so I didn't expect this from a flatbed
scanner. So, I think I will probably just scan negatives from now on.
It's a tad slower, but the quality is better. Sharper, better color
balance, and the white horses aren't glowing.
 
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